A series of 3.0Mo/(Hβ+γ-Al_(2)O_(3))samples withγ-Al_(2)O_(3)contents in the range of 0_100%(mass fraction)was studied by means of XRD,NH_(3)-TPD,TPR and BET determinations for characterizing their structures.The H...A series of 3.0Mo/(Hβ+γ-Al_(2)O_(3))samples withγ-Al_(2)O_(3)contents in the range of 0_100%(mass fraction)was studied by means of XRD,NH_(3)-TPD,TPR and BET determinations for characterizing their structures.The Hβzeolite structure in the 3.0Mo/Hβsample can be effectively stabilized by adding someγ-Al_(2)O_(3)to Hβzeolite.γ-Al_(2)O_(3)mainly favors the formation of polymolybdate or multilayered Mo oxide,while Hβmainly forms the Al_(2)(MoO_(4))_(3)species,as evaluated by the TPR technique.When used as the catalyst for the metathesis of butylene-2 and ethylene to propylene,there exists a close correlation between the specific surface area and stability of the catalyst.The specific surface area of the catalyst shows the maximum when{(Hβ+}γ-Al_(2)O_(3))contains 30%γ-Al_(2)O_(3),which is in agreement with that of the time needed for the reaction stablization.In the case of maximum surface area,the rate of coke deposition is the minimum.展开更多
基金the National Natural Science Foundation of China(No.20303019)the National 973 Project of China(No.2003CB615802).
文摘A series of 3.0Mo/(Hβ+γ-Al_(2)O_(3))samples withγ-Al_(2)O_(3)contents in the range of 0_100%(mass fraction)was studied by means of XRD,NH_(3)-TPD,TPR and BET determinations for characterizing their structures.The Hβzeolite structure in the 3.0Mo/Hβsample can be effectively stabilized by adding someγ-Al_(2)O_(3)to Hβzeolite.γ-Al_(2)O_(3)mainly favors the formation of polymolybdate or multilayered Mo oxide,while Hβmainly forms the Al_(2)(MoO_(4))_(3)species,as evaluated by the TPR technique.When used as the catalyst for the metathesis of butylene-2 and ethylene to propylene,there exists a close correlation between the specific surface area and stability of the catalyst.The specific surface area of the catalyst shows the maximum when{(Hβ+}γ-Al_(2)O_(3))contains 30%γ-Al_(2)O_(3),which is in agreement with that of the time needed for the reaction stablization.In the case of maximum surface area,the rate of coke deposition is the minimum.
